Argentine ant

harms crops
 

harms people
 

harms wildlife
 

lives in trees
 

lives on ground 
 

day active 

Scientific name: Linepithema humile

Size: 2-3 mm

Colour: uniform dull brown

General description: the Argentine ant is a small ant, which is smooth and shiny with no hairs. It forms well-defined trails to and from food sources. Workers look the same (monomorphic).

Habitat and nesting: Argentine ants are typically ground dwelling and favour moist environments for nesting. Nests may be found under piles of wood, stones, under or amongst rubbish, under buildings, in potted plants or in piles of leaves or other organic debris. These ants mostly nest outside, but may move into houses or other buildings if their outdoor nests are disturbed.

Rate of spread: 15-270 m/year in Northern California.

Distribution: see our invasive ant distributions page for the worldwide distribution of the Argentine ant.

 

Argentine ant worker (© Alex Wild)

Argentine ant queen (bottom centre) and workers (© Phil Lester)

Reproduction: Argentine ant colonies reproduce by budding. If the queens in the colony die, workers can cause eggs and larvae to become new queens. This feature makes eradication more complex.

Development: eggs hatch into larvae in 15-55 days (average 28 days). Larvae develop for 11-61 days (average 31 days) before becoming a pupae. Workers remain pupae for 8-25 days (average 20 days), then emerge as adults. Development is quicker when temperatures are warmer.

For detailed descriptions and identification of Argentine ants please see:

PIAkey: Linepithema humile (see diagnostic characters tab)

AntWeb: Linepithema humile

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Impacts of the Argentine ant

Social

Argentine ants are the only species among the worst 5 invasive ants that does not sting, spray acid on or bite people. However, this ant can be extremely annoying because it likes living indoors and can invade homes in huge numbers, contaminating any food that it can get into (which is essentially anything not in a sealed bag or tin).

Agricultural

Argentine ants tend sap-sucking insects, causing pest outbreaks and damaging crops.

Argentine ants also raid beehives, causing losses of up to 50% of the hives of some beekeepers!

Argentine ants tending mealybugs (© Phil Lester)
 
Argentine ants foraging on a dead moth (© Phil Lester)
 
Argentine ants swarming over honey comb (© Jess Russell)

Environmental

Unlike many invasive ant species, which prefer areas of human disturbance, Argentine ants can easily spread into pristine areas where they do even more damage to native species.

Argentine ants interfere with pollination and seed dispersal of native plants. They also replace other ant species and have a negative effect on many native invertebrates.

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Management

If you are interested in getting rid of Argentine ants, check out the treatment options for this species, or look at management programme case studies to see examples of other control programmes that target them.

Information sources

Abril, Oliveras, Gómez. 2010. Effect of temperature on the development and survival of the Argentine ant, Linepithema humile. Journal of Insect Science 10:97. Creative Commons Attribution 3.0 License

Animal Diversity Web, Argentine ants

Argentine ants in New Zealand website

Clemson University website, Argentine ants

Global Invasive Species Database, Argentine ant

Global Register of Introduced and Invasive Species (GRIIS)

Holway, Lach, Suarez, Tsutsui and Case. 2002. The causes and consequences of ant invasions. Annual Review of Ecology, Evolution, and Systematics 33: 181-233

Landcare Research Manaaki Whenua Ant Factsheet, Argentine ant

Orkin website, Argentine ants

Russell, Brenton-Rule, Saunders, Lester. 2016. Argentine ant interactions with bees. unpublished data

Passera, Keller, Suzzoni. 1988. Queen replacement in dequeened colonies of the Argentine ant Iridomyrmex humilis (Mayr). Psyche. 95:59-65

Suarez, Holway, Case. 2001. Patterns of spread in biological invasions dominated by long-distance jump dispersal: insights from Argentine ants. PNAS 98(3): 1095-1100

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